The present invention relates to a coupling assembly for mounting a heating element to an opening in an engine block, and more particularly, to a guide member which prevents blow-out of the coupling assembly from the engine block opening when pressure is exerted against the coupling assembly by the engine coolant after the engine has reached an operating or higher temperature.
In colder temperatures, a diesel engine is difficult to start until the air which is drawn into the cylinders becomes heated to a high temperature (approx. 700.degree.-900.degree. C). Diesel fuel can be injected into the cylinders and spontaneously ignited only when the intake air has reached this highly heated state. It is conventional to provide an engine block heater for use in diesel engines which warms the engine coolant to assist in the starting of the engine. The heater element warms the engine coolant prior to engine starting, and the warmed engine coolant circulates around the cylinder walls to thereby help in the heating of the air drawn into the cylinders.
The engine block heater includes a heating element which is mounted by a coupling assembly to an opening through the side of the engine block. The heating element is disposed inside the engine block to heat the engine coolant. After the engine has been started and it reaches its normal operating temperature and above, the pressure exerted by the hot engine coolant against the coupling assembly is substantial and has resulted in some instances in a blowout of the coupling assembly from the engine block opening. The prior art coupling assemblies have been ineffective in preventing a blow-out of the engine block heater when the engine coolant becomes highly heated and exerts substantial pressure against the coupling assembly.
Thus, the disadvantages of present coupling assemblies for engine block heaters have resulted in the present invention which effectively reduces or eliminates the possibility of engine block heater blow-out.